As of September 29, 2026, IDEAYA Biosciences's top three insider holders are Yujiro S Hata (President And Ceo, 690.70K shares), Michael P. Dillon (Svp, Chief Scientific Officer, 78.79K shares), Jason Throne (Chief Legal Officer, 63.48K shares).
| # | Insider | Position | Direct | Indirect | Total | Share of Insiders | Last Filed |
|---|---|---|---|---|---|---|---|
| 1 | Yujiro S Hata | President And Ceo | 690,695 | 0 | 690,695 | 74.7% | 19 Feb, 2025 |
| 2 | Michael P. Dillon | Svp, Chief Scientific Officer | 78,789 | 0 | 78,789 | 8.5% | 06 Oct, 2021 |
| 3 | Jason Throne | Chief Legal Officer | 63,484 | 0 | 63,484 | 6.9% | 27 Jun, 2024 |
| 4 | Jeffrey Stein | Director | 54,281 | 0 | 54,281 | 5.9% | 02 Mar, 2026 |
| 5 | Briseno Andres Ruiz | Chief Accounting Officer | 26,466 | 0 | 26,466 | 2.9% | 09 Jul, 2026 |
| 6 | Paul A. Stone | Chief Financial Officer | 9,303 | 0 | 9,303 | 1.0% | 31 Aug, 2023 |
| 7 | Douglas B. Snyder | Svp, General Counsel | 2,080 | 0 | 2,080 | 0.2% | 02 Feb, 2026 |
Each row is that insider’s most recently reported position, from Form 4 filings over the last 60 months — which is why this total does not tie to the quarterly series above, where a quarter counts only the insiders who filed in it. Shares held through a fund or institutional portfolio are counted on the institutional ownership page instead.
| Date | Insider | Position | Transaction | Shares | Price | Value | Shares Held After | Ownership |
|---|---|---|---|---|---|---|---|---|
| 07 Jul, 2026 | Briseno Andres Ruiz | Chief Accounting Officer | Acquired M | 9,550 | $12.86 | $122.81K | 36,016 | Direct |
| 07 Jul, 2026 | Briseno Andres Ruiz | Chief Accounting Officer | Disposed S | 9,550 | $40.01 | $382.13K | 26,466 | Direct |
| 07 Jul, 2026 | Briseno Andres Ruiz | Chief Accounting Officer | Disposed M | 9,550 | $0.00 | $0 | 19,200 | Direct |
| 16 Jun, 2026 | Jeffrey Stein | Director | Acquired A | 20,000 | $0.00 | $0 | 20,000 | Direct |
| 16 Jun, 2026 | Wendy L Yarno | Director | Acquired A | 20,000 | $0.00 | $0 | 20,000 | Direct |
| 16 Jun, 2026 | Catherine J Mackey | Director | Acquired A | 20,000 | $0.00 | $0 | 20,000 | Direct |
| 16 Jun, 2026 | Terry J Rosen | Director | Acquired A | 20,000 | $0.00 | $0 | 20,000 | Direct |
| 16 Jun, 2026 | Malcolm Garret Hampton | Director | Acquired A | 20,000 | $0.00 | $0 | 20,000 | Direct |
| 16 Jun, 2026 | Scott W Morrison | Director | Acquired A | 20,000 | $0.00 | $0 | 20,000 | Direct |
| 02 Mar, 2026 | Jeffrey Stein | Director | Acquired P | 50,000 | $32.96 | $1.65Mn | 54,281 | Direct |
| 29 Nov, 2024 | Briseno Andres Ruiz | Officer | Acquired A | 682 | $23.26 | $15.86K | 25,213 | Direct |
| 30 May, 2025 | Douglas B. Snyder | Svp, General Counsel | Acquired A | 1,039 | $16.91 | $17.57K | 1,039 | Direct |
| 30 Jan, 2026 | Stuart Dorman | Chief Commercial Officer | Acquired A | 155,000 | $0.00 | $0 | 155,000 | Direct |
| 30 Jan, 2026 | Darrin Beaupre | Chief Medical Officer | Acquired A | 175,000 | $0.00 | $0 | 175,000 | Direct |
| 30 Jan, 2026 | Michael Anthony White | Chief Scientific Officer | Acquired A | 190,000 | $0.00 | $0 | 190,000 | Direct |
| 30 Jan, 2026 | Yujiro S Hata | President And Ceo | Acquired A | 600,000 | $0.00 | $0 | 600,000 | Direct |
| 30 Jan, 2026 | Joshua Bleharski | Chief Financial Officer | Acquired A | 170,000 | $0.00 | $0 | 170,000 | Direct |
| 28 Nov, 2025 | Douglas B. Snyder | Svp, General Counsel | Acquired A | 1,041 | $16.91 | $17.60K | 2,080 | Direct |
| 28 Nov, 2025 | Briseno Andres Ruiz | Officer | Acquired A | 1,253 | $16.91 | $21.18K | 26,466 | Direct |
| 30 Jan, 2026 | Briseno Andres Ruiz | Officer | Acquired A | 80,000 | $0.00 | $0 | 80,000 | Direct |